There is known an erroneous fuel feed prevention device to be provided on a fuel feed passage in a vehicle such as an automobile to block insertion of a small-diameter fuel feeding nozzle and permit insertion of a large-diameter fuel feeding nozzle. For example, Patent Literature 1 describes a technique for blocking or permitting insertion of a fuel feeding nozzle using paired flaps (shutter members) that open from and close at the center of a fuel feed passage.
A long bearing hole is formed in each flap. A turn shaft member provided to a bearing bracket portion of a housing engages with the bearing hole, and thus the flap is turnable and is slidable in a radial direction of the fuel feed passage.